From ksuzuki@cmu.edu Tue Oct 18 04:36:39 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!cmu!ksuzuki From: ksuzuki@cmu.edu (Kenji Suzuki) Newsgroups: comp.dsp Subject: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct18.043639.1976@cmu.edu> Date: Tue, 18 Oct 1994 04:36:39 GMT Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. Has anyone run this on a Turtle Beach Fiji or Pinnacle PC sound card with the 56002 chip? -- Kenji Suzuki | ksuzuki@cmu.edu PGP Key fingerprint: 4F03 8BE9 0BBA E8D8 "Keep the channels open." From mperez@demon.co.uk Tue Oct 18 07:44:39 1994 Path: ashpoly!cascade!bigsur!demon!mperez From: mperez@demon.co.uk (Morag Pérez) Newsgroups: comp.dsp Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct18.074439.4994@demon.co.uk> Date: Tue, 18 Oct 1994 07:44:39 GMT References: <1994Oct18.043639.1976@cmu.edu> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1994Oct18.043639.1976@cmu.edu>, ksuzuki@cmu.edu (Kenji Suzuki) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Morag Pérez -- Demon Internet Services UK "5 sigma is a discovery. 7 is a question." From bfischer@uni-hamburg.de Wed Oct 19 03:35:39 1994 Path: ashpoly!cascade!bigsur!uni-hamburg!bfischer From: bfischer@uni-hamburg.de (Bastien Fischer) Newsgroups: comp.dsp Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct19.033539.2337@uni-hamburg.de> Date: Wed, 19 Oct 1994 03:35:39 GMT References: <1994Oct18.043639.1976@cmu.edu> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: Netscape 1.1N Lines: 9 In article <1994Oct18.043639.1976@cmu.edu>, ksuzuki@cmu.edu (Kenji Suzuki) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Bastien Fischer "The hatch is open. Is anyone listening?" Macintosh IIfx / System 7.5.1 From csokolov@mindspring.com Wed Oct 19 06:20:39 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!mindspring!csokolov From: csokolov@mindspring.com (Callum Sokolov) Newsgroups: comp.dsp Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct19.062039.6468@mindspring.com> Date: Wed, 19 Oct 1994 06:20:39 GMT References: <1994Oct18.043639.1976@cmu.edu> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: Netscape 1.1N Lines: 10 In article <1994Oct18.043639.1976@cmu.edu>, ksuzuki@cmu.edu (Kenji Suzuki) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Callum Sokolov -- MindSpring Enterprises "5 sigma is a discovery. 7 is a question."